Ore dissolving device and method

Abstract

The present invention relates to the technical field of industrial solid waste utilization, and specifically relates to an ore dissolving device and method. The ore dissolving device comprises a tank body, and an ore dissolving area, a ore-dissolving slag removal area, an iron and aluminum removal area and a leaching solution storage area, which are sequentially arranged in the tank body from top to bottom, wherein the bottom of the ore dissolving area is in communication with the ore-dissolving slag removal area; a plurality of first overflow pipes are evenly provided in the ore-dissolving slag removal area, one end of each first overflow pipe is in communication with the ore-dissolving slag removal area, and the other end thereof is in communication with the iron and aluminum removal area; a plurality of second overflow pipes are evenly provided in the iron and aluminum removal area, one end of each second overflow pipe is in communication with the iron and aluminum removal area, and the other end thereof is in communication with the leaching solution storage area; and one or more precipitant sprayers are also provided above the iron and aluminum removal area. The ore dissolving device of the present invention can not only fully leach calcium from magnesium slag, with a calcium extraction rate of 90% or higher, but can also effectively remove impurities such as iron and aluminum in an ore dissolving solution, thereby improving the purity of calcium ions in a leaching solution.

Description

Ore dissolving device and method This application claims priority to the Chinese patent application filed with the Patent Office of China on November 29, 2023, with application number 202311616103.6 and invention name “A device and method for dissolving ore”, the entire contents of which are incorporated herein by reference. Technical Field

[0001] The present invention relates to the technical field of industrial solid waste utilization, and in particular to an ore dissolving device and method for purifying power plant flue gas using magnesium slag. Background Art

[0002] Light calcium carbonate, an important inorganic chemical raw material, is widely used in industries such as papermaking, rubber, plastics, coatings, pharmaceuticals, and food. It is particularly popular as a filler in the paper industry. Currently, light calcium carbonate is mostly produced using the carbonization method, which involves calcining limestone to produce lime. The lime is then digested to produce lime slurry, into which carbon dioxide generated by the calcined limestone is introduced for carbonization, producing calcium carbonate.

[0003] Currently, flue gas from thermal power plants is mostly discharged directly into the atmosphere after undergoing desulfurization, denitrification, and dust removal. This flue gas still contains a certain concentration of carbon dioxide, which remains unused, resulting in both resource waste and environmental pollution. Currently, a more stable method for carbon dioxide sequestration is to convert it into carbonate minerals such as calcium carbonate and magnesium carbonate.

[0004] For example, CN114933323A discloses a method for producing high-purity calcium carbonate using ammonium chloride in combination with carbon dioxide to treat waste cement powder. This method employs a "leaching-carbonization" cycle, which can sequester large amounts of carbon dioxide and extract 97.8% pure calcium carbonate from waste cement powder. However, this method requires the addition of ammonia for pH adjustment and is only in the pilot stage, without considering the three waste treatment issues associated with industrial scale-up.

[0005] CN109704380A discloses a method for continuously preparing light calcium carbonate filler using power plant flue gas, which digests lime with hot water to obtain a coarse pulp. After the coarse pulp is concentrated, it is vibrated and screened and a suspension separator is used to remove impurities to obtain a refined pulp. The refined pulp is then poured into a carbonizing tower, a crystal form control agent is added, and after stirring evenly, the treated power plant flue gas is introduced for carbonization. During the carbonization process, pH and conductivity are detected online, and the carbonization end point is determined by pH and conductivity. A pH regulator is added to the carbonized cooked pulp, and impurities are removed through a 325 mesh sieve to finally obtain a light calcium carbonate filler. However, this method requires the addition of a pH regulator and a crystal form control agent. The subtle changes in the solution cannot be accurately determined by pH and conductivity, and more storage tanks are required to store acid and alkali, which poses a safety hazard. In addition, the crystal form control agent will also adhere to the product, resulting in a decrease in the purity of calcium carbonate.

[0006] CN111214938A discloses a carbon dioxide mineralization reaction device and carbon dioxide fixation method. This device, which eliminates the need for a separate carbon dioxide capture process and can capture carbon dioxide from exhaust gas, simultaneously converts the carbon dioxide into a carbonate mineral form with high efficiency and purity. This method minimizes the volume of the process equipment, improving space efficiency and enabling high conversion rates of carbon dioxide into carbonate mineral form even at room temperature and pressure. However, this device requires the electrolysis of hydrochloric acid for subsequent mineralization, which consumes a large amount of electricity and results in high carbon fixation costs.

[0007] Magnesium slag is an industrial waste produced during magnesium smelting using the silicon-thermal process. According to statistics, the production of 1 ton of primary magnesium produces 5.5-10 tons of magnesium reduction slag. Currently, magnesium smelters primarily dispose of magnesium slag waste by landfilling or dumping it in fixed locations. These irrational disposal methods not only cause environmental pollution, such as air and soil pollution, but also result in a significant waste of resources.

[0008] In recent years, with the rapid development of my country's magnesium smelting industry, the annual output of primary magnesium and magnesium alloys has increased year by year, resulting in an increasing amount of magnesium slag emissions. Magnesium slag, with its high silicon, magnesium, and calcium contents, can be used to absorb carbon dioxide from flue gases and generate economically viable calcium-magnesium carbonate. This not only reduces emissions but also plays a significant role in addressing the pollution problem of magnesium reduction slag.

[0009] For example, CN116282116A discloses a circulation process for the mineralization of carbon dioxide from magnesium slag, which is leached by ammonium chloride and the carbon dioxide is sealed in situ using the leachate to prepare high-purity calcium carbonate and magnesium carbonate products. The process can process magnesium slag solid waste such as steel slag and carbide slag and carbon dioxide in factory tail gas, and simultaneously prepare high value-added products such as calcium carbonate and magnesium carbonate. The ammonium chloride solution is also recycled, and the process does not produce wastewater or waste gas. However, this method has not yet considered the impact of impurities such as iron and aluminum in magnesium slag on the effect of carbon dioxide mineralization.

[0010] In view of this, the present invention is proposed. Summary of the Invention

[0011] The object of the present invention is to provide a ore dissolving device and method, which can not only fully leach calcium from magnesium slag with a calcium extraction rate of more than 95%, but also effectively eliminate impurities such as iron and aluminum in the ore dissolving solution, thereby improving the purity of calcium ions in the leaching solution.

[0012] In a first aspect, the present invention provides an ore dissolving device, comprising a tank body and an ore dissolving area, an ore dissolving and slag removal area, an iron and aluminum removal area, and a leachate storage area sequentially arranged inside the tank body from top to bottom.

[0013] The bottom of the ore dissolution zone is connected to the ore dissolution and slag removal zone.

[0014] A plurality of first overflow pipes are evenly arranged in the desolventizing filter residue area, and one end of each of the first overflow pipes is connected to the desolventizing filter residue area, and the other end is connected to the iron and aluminum removal area;

[0015] A plurality of second overflow pipes are evenly arranged in the de-ironing and de-aluminum zone, and one end of each of the second overflow pipes is connected to the de-ironing and de-aluminum zone, and the other end is connected to the leachate storage zone;

[0016] One or more precipitant sprayers are also provided above the iron and aluminum removal zone.

[0017] As a preferred embodiment of the present technical solution, the bottoms of the ore dissolution zone, the ore dissolution residue removal zone, and the iron and aluminum removal zone are all conical structures, and the bottoms of the ore dissolution zone, the ore dissolution residue removal zone, and the iron and aluminum removal zone are respectively provided with a first mixed liquid outlet, a second mixed liquid outlet, and a third mixed liquid outlet;

[0018] The second mixed liquor outlet is communicated with the upper portion of the ore dissolution and slag removal zone through a first pipeline, and the third mixed liquor outlet is communicated with the upper portion of the iron and aluminum removal zone through a second pipeline.

[0019] As a preferred embodiment of the present technical solution, a first filter and a second filter are respectively provided on the first pipe and the second pipe.

[0020] As a preferred embodiment of the present technical solution, a plurality of sedimentation wedge assemblies are provided inside the ore removal and slag removal zone and the iron and aluminum removal zone, and the sedimentation wedge assemblies include a plurality of inwardly inclined first sedimentation wedges and a plurality of outwardly inclined second sedimentation wedges, and the second sedimentation wedges are arranged above the first sedimentation wedges.

[0021] As a preferred embodiment of the present technical solution, a feed port, a liquid replenishment port and an exhaust gas discharge port are provided on the top of the ore dissolution zone, a feed port is provided with a feed discharge mechanism, and an iron removal component is provided at one end of the feed port close to the feed port.

[0022] As a preferred embodiment of the present technical solution, a stirring mechanism is provided inside the ore dissolving zone, and a circulating water heating layer is provided outside the ore dissolving zone.

[0023] As a preferred embodiment of the present invention, an online liquid level meter is provided inside the ore dissolution zone, and an online viscosity detector is installed at the outlet of the first mixed liquid;

[0024] An extraction liquid outlet is provided at the bottom of the extraction liquid storage area, and an online calcium ion monitor and a flow meter are installed at the extraction liquid outlet;

[0025] The valves at the first mixed liquid outlet and the leachate outlet are both pneumatic regulating valves.

[0026] In a second aspect, the present invention further discloses a method for dissolving ore using the above-mentioned ore dissolving device, comprising the following steps:

[0027] S1, magnesium slag enters the ore dissolution area through the feeding mechanism, and the magnesium slag is leached by ammonium chloride, and the resulting ore dissolution liquid enters the ore dissolution and slag removal area through the first mixed liquid outlet;

[0028] S2. In the ore removal residue removal zone, the molten ore solution is settled by the settling wedge assembly and then enters the first filter through the second mixed liquid outlet. The resulting filtrate returns to the ore removal residue removal zone; the supernatant in the ore removal residue removal zone overflows to the iron and aluminum removal zone through multiple first overflow pipes;

[0029] S3. In the iron and aluminum removal area, the precipitant sprayer sprays the precipitant on the surface of the overflow liquid. After the mixed liquid is settled by the settling wedge assembly, it enters the second filter through the third mixed liquid outlet, and the resulting filtrate returns to the iron and aluminum removal area again; the supernatant in the iron and aluminum removal area overflows into the leachate storage area through multiple second overflow pipes and is discharged from the leachate outlet.

[0030] As a preferred embodiment of the present technical solution, in step S1, the feeding rate of magnesium slag is 550-700 kg / h, the mass ratio of magnesium slag to ammonium chloride is 1:(1.0-1.2), and the mass concentration of ammonium chloride is 6-12%.

[0031] As a preferred embodiment of the present technical solution, in step S3, the precipitant includes any one or more of ammonia water, sodium hydroxide, sodium carbonate and ammonium bicarbonate, and the volume ratio of the precipitant to the overflow liquid is 1:(10-15), wherein the molar concentration of the precipitant is 0.01-0.02 mol / L.

[0032] Compared with the prior art, the ore dissolving device and method of the present invention have at least the following effects:

[0033] 1. The ore dissolving device of the present invention is provided with an ore dissolving area, an ore dissolving residue removal area, an iron and aluminum removal area, and a leachate storage area in order from top to bottom. In the ore dissolving area, ammonium chloride is used to leach calcium ions in the magnesium slag, and the leached ore solution enters the ore dissolving residue removal area; after the calcium carbonate, silicon dioxide and other impurities in the ore dissolving solution are precipitated and filtered out in the ore dissolving residue removal area, the supernatant overflows to the iron and aluminum removal area; in the iron and aluminum removal area, the precipitant is used to remove impurities such as iron and aluminum in the mixed solution, and the supernatant further overflows to the leachate storage area. Therefore, the ore dissolving device of the present invention can fully leach calcium in the magnesium slag under the interaction of the ore dissolving area, the ore dissolving residue removal area, the iron and aluminum removal area, and the leachate storage area, with a calcium extraction rate of more than 90%, and can effectively eliminate impurities such as iron and aluminum in the ore dissolving solution, thereby improving the purity of calcium ions in the leachate;

[0034] 2. When the leachate produced by the ore dissolution device of the present invention is used for carbon dioxide mineralization absorption, high-purity calcium carbonate can be obtained, with a carbon dioxide absorption rate of over 95%. During operation, no acid or alkali is required to adjust the pH, and no crystal form control agent is required. Tests have shown that the calcium carbonate obtained by this method is 200-300% more efficient than the heavy calcium carbonate used in power plant desulfurization, and no grinding is required, significantly reducing energy consumption.

[0035] 3. The ore dissolution device of the present invention reduces floor space, comprehensively utilizes space, reduces water transport in the absorption and separation units, improves process efficiency, reduces process energy consumption, and has low operating costs;

[0036] 4. The ore dissolving device of the present invention has a simple process. Through the online calcium ion monitor, ammonia concentration monitor, viscosity detector and conductivity detector, the reaction process can be automatically controlled by PLC to achieve fully automated production;

[0037] 5. The present invention utilizes magnesium slag to purify power plant flue gas for ore dissolution. While reducing waste gas emissions, the present invention uses magnesium slag discharged from a metal magnesium plant to recycle carbon dioxide from the waste gas. During the reaction, the leaching liquid is used to fix carbon, the generated ammonium chloride and washing water are recycled, the water vapor in the flue gas is cooled and used as production water, and the heat from the flue gas is used as a heat source for the ore dissolution reaction. The tail gas generated during the production process contains ammonia, which can be piped into a denitrification system, and the waste slag generated during the production process can be used as a raw material for a cement plant. Therefore, the present invention can fully utilize the three wastes, resulting in good economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0039] FIG1 is a schematic structural diagram of an ore dissolving device according to the present invention;

[0040] FIG2 is a schematic diagram of the ore dissolving device of the present invention;

[0041] FIG3 is a flow chart of the present invention for purifying power plant flue gas using magnesium slag.

[0042] Reference numerals:

[0043] 1: ore dissolution area; 2: ore dissolution and slag removal area; 3: iron and aluminum removal area; 4: leachate storage area; 5: first overflow pipe; 6: second overflow pipe; 7: precipitant sprayer; 8: first mixed liquor outlet; 9: second mixed liquor outlet; 10: third mixed liquor outlet; 11: first pipeline; 12: second pipeline; 13: first filter; 14: second filter; 15: first sedimentation wedge; 16: second sedimentation wedge; 17: feed port; 18: liquid replenishment port; 19: tail gas discharge port; 20: feeding mechanism; 21: iron removal component; 22: stirring mechanism; 23: circulating water heating layer; 24: leachate outlet. DETAILED DESCRIPTION

[0044] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0045] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular also includes the plural. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0046] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0047] Example 1

[0048] As shown in FIG1-2, this embodiment provides a ore dissolving device, comprising a tank body and an ore dissolving area 1, an ore dissolving and slag removal area 2, an iron and aluminum removal area 3, and a leachate storage area 4, which are sequentially arranged inside the tank body from top to bottom.

[0049] The bottom of the ore dissolution area 1 is connected to the ore dissolution residue removal area 2, that is, the ore dissolution liquid obtained in the ore dissolution area 1 can directly enter the ore dissolution residue removal area 2; a plurality of first overflow pipes 5 are evenly arranged in the ore dissolution residue removal area 2, and one end of each first overflow pipe 5 is connected to the ore dissolution residue removal area 2, and the other end is connected to the iron and aluminum removal area 3, that is, the supernatant after sedimentation and separation in the ore dissolution residue removal area 2 can overflow to the iron and aluminum removal area 3 through the first overflow pipe 5 to further remove impurities such as iron and aluminum in the ore dissolution liquid; a plurality of second overflow pipes 6 are evenly arranged in the iron and aluminum removal area 3, and one end of each second overflow pipe 6 is connected to the iron and aluminum removal area 3, and the other end is connected to the leaching liquid storage area 4; one or more precipitant sprayers 7 are also arranged above the iron and aluminum removal area 3, and spraying the precipitant on the overflow liquid surface through the precipitant sprayer 7 can effectively precipitate the iron and aluminum ions in the ore dissolution liquid.

[0050] In the ore dissolution area 1 of this embodiment, ammonium chloride is used to leach calcium ions in the magnesium slag, and the leached ore solution enters the ore dissolution filter area 2; after impurities such as calcium carbonate and silicon dioxide in the ore dissolution solution are precipitated and filtered out in the ore dissolution filter area 2, the supernatant overflows to the aluminum and iron removal area; in the iron and aluminum removal area 3, impurities such as iron and aluminum in the mixed solution are removed by a precipitant, and the resulting supernatant further overflows to the leachate storage area 4 and can be used for carbon dioxide mineralization absorption.

[0051] Therefore, the ore dissolving device of the present invention can not only fully leach calcium in the magnesium slag under the interaction of the ore dissolving area 1, the ore dissolving filter residue removal area 2, the iron and aluminum removal area 3 and the leachate storage area 4, with a calcium extraction rate of more than 95%, but also effectively eliminate impurities such as iron and aluminum in the ore dissolving solution, thereby improving the purity of calcium ions in the leachate.

[0052] When the above-mentioned leachate is used for carbon dioxide mineralization and absorption, the whiteness and purity of the calcium carbonate can be significantly improved, increasing the added value of the product. The carbon dioxide absorption rate can reach over 95%. During operation, the ammonia generated by the magnesium slag and ammonium chloride can form a buffer solution with the ammonium chloride. Therefore, during the mineralization process, there is no need to add acid or alkali to adjust the pH, and there is no need to add crystal form control agents. According to tests, the calcium carbonate obtained by this method is 200-300% more efficient than the heavy calcium carbonate used in power plant desulfurization, and no grinding is required, which significantly reduces energy consumption.

[0053] On the basis of the above technical scheme, it is further preferred that the bottoms of the ore dissolution zone 1, the ore dissolution residue zone 2 and the iron-aluminum removal zone 3 are all conical structures to improve the precipitation effect of the ore dissolution solution in each zone, and the residue is enriched at the bottom of the ore dissolution residue zone 2 and the iron-aluminum removal zone 3, and the bottoms of the ore dissolution zone 1, the ore dissolution residue zone 2 and the iron-aluminum removal zone 3 are respectively provided with a first mixed liquor outlet 8, a second mixed liquor outlet 9 and a third mixed liquor outlet 10; the ore dissolution zone 1 enters the ore dissolution residue zone 2 through the first mixed liquor outlet 8, the second mixed liquor outlet 9 is connected to the top of the ore dissolution residue zone 2 through the first pipeline 11, so as to transport the mixture of the filtrate and residue of the ore dissolution residue zone 2 back to the ore dissolution residue zone 2 for further sedimentation, and the third mixed liquor outlet 10 is connected to the top of the iron-aluminum removal zone 3 through the second pipeline 12, so as to transport the mixture of the filtrate and residue of the iron-aluminum removal zone 3 back to the iron-aluminum removal zone 3 for further sedimentation.

[0054] In this embodiment, in order to timely filter out the filter residue produced in the desolventizing filter residue area 2 and the iron and aluminum removal area 3, a first filter 13 and a second filter 14 are respectively provided on the first pipe 11 and the second pipe 12. The filtrate after being filtered by the first filter 13 and the second filter 14 enters the desolventizing filter residue area 2 and the iron and aluminum removal area 3 respectively for further sedimentation and separation. Among them, the filter residue produced by the first filter 13 can be transported to the cement plant as raw material for cement production, and the filter residue produced by the second filter 14 can be directly transported to the steel plant.

[0055] On the basis of the above technical solution, to further improve the sedimentation effect of the ore removal filter residue zone 2 and the iron and aluminum removal zone 3, multiple sedimentation wedge assemblies are installed inside the ore removal filter residue zone 2 and the iron and aluminum removal zone 3. The present invention does not strictly limit the structure and arrangement of the sedimentation wedge assemblies. Specifically, the sedimentation wedge assemblies may include multiple inwardly inclined first sedimentation wedges 15 and multiple outwardly inclined second sedimentation wedges 16, wherein the second sedimentation wedges 16 are arranged above the first sedimentation wedges 15. Therefore, the second sedimentation wedges 16 and the first sedimentation wedges 15 can sequentially sediment and separate the molten ore.

[0056] In this embodiment, a feed port 17, a liquid replenishment port 18 and an exhaust gas discharge port 19 are sequentially provided on the top of the ore dissolution area 1, wherein a feeding mechanism 20 is provided on the feed port 17, and an iron removal component 21 is provided at one end of the feeding mechanism 20 close to the feed port 17. Magnesium slag is injected into the ore dissolution area 1 through the feeding mechanism 20. While discharging, the iron removal component 21 can remove the magnetic iron element or iron oxide compound in the magnesium slag; the liquid replenishment port 18 is mainly used for replenishing ammonium chloride solution; the exhaust gas discharge port 19 is mainly used to discharge the waste gas generated during the ore dissolution process, and the waste gas generated is connected to the exhaust gas emission generated by the mineralization reaction device and enters the denitrification system of the power plant in a unified manner.

[0057] Specifically, a stirring mechanism 22 is provided inside the ore dissolution area 1 to increase the disturbance degree of the leaching system and improve the leaching efficiency. In addition, a circulating water heating layer 23 is also provided outside the ore dissolution area 1 to heat the leaching system. A circulating water inlet and a circulating water outlet are provided on the circulating water heating layer 23. The circulating water is mainly provided by the flue gas cooling tower of the power plant. One pipe of the cooling tower outlet pipe supplies the circulating water heating layer 23, and the other is connected to the circulating water system. The obtained condensed water is stored in a water tank.

[0058] Based on the above technical solution, it is further preferred that an online liquid level gauge be installed inside the ore dissolution zone 1 to monitor the liquid level in real time. A PLC-controlled metering pump replenishes the liquid from an ammonium chloride tank. The ammonium chloride used here is produced during the carbon dioxide mineralization reaction and can therefore be recycled within the device. Furthermore, an online viscosity tester is installed at the first mixed liquid outlet 8, and the flow rate of the mixed liquid flowing into the ore dissolution and slag removal zone 2 is automatically adjusted by a PLC controller.

[0059] An leachate outlet 24 is provided at the bottom of the leachate storage area 4, and an online calcium ion monitor and a flow meter are installed at the leachate outlet 24. The flow rate is adjusted by the calcium ion concentration to connect the leachate to the carbon dioxide mineralization device, and the carbon dioxide conversion rate is calculated by the PLC controller to automatically control the flow entering the mineralization device.

[0060] The valves at the first mixed liquid outlet 8 and the leachate outlet 24 are preferably pneumatic regulating valves.

[0061] As shown in Figure 3, the leaching solution obtained in this embodiment can be directly pumped into the carbon dioxide absorption and mineralization device to absorb the carbon dioxide in the flue gas of the power plant. The flue gas of the power plant is dehydrated and impurities removed by a cooling tower and a filter tower. The cooled water is used to prepare the product slurry. The treated flue gas is passed through a compressor into the carbon dioxide absorption and mineralization device. An online carbon dioxide concentration analyzer is installed at the flue gas inlet and outlet. The flow rate of the leaching solution is automatically adjusted by the PLC controller according to the changes in carbon dioxide and calcium ion concentrations. Since magnesium slag and ammonium chloride generate ammonia gas and form a buffer solution with ammonium chloride, there is no need to add a pH regulator during the mineralization reaction. After the mineralized liquid enters the sedimentation tank for precipitation, the bottom slurry is pumped into a filter press for filtration, and the filtrate enters the ammonium chloride concentration equipment. The concentrated solution is returned to the ammonium chloride storage tank, and the condensed water returns to the water tank. The filter cake is prepared into a slurry of 1180-1250kg / m according to the density. 3The ore dissolution device in this embodiment is used to address CO2 emissions from power plants, not only improving CO2 absorption but also enabling fully automated production, reducing labor costs.

[0062] Example 2

[0063] The most preferred ore dissolution device was used to treat magnesium slag discharged from a metal magnesium plant, and its main components were determined by melt X-ray fluorescence spectrometry. The results are shown in Table 1.

[0064] Table 1 XRF composition analysis of magnesium slag

[0065]

[0066] The specific steps include:

[0067] S1, magnesium slag enters the ore dissolution zone 1 through the feeding mechanism 20, the feeding speed is 550kg / h, the ammonium chloride solution is replenished from the ammonium chloride tank through the PLC-controlled metering pump, the concentration of the ammonium chloride solution is 10%, the mass ratio of magnesium slag to ammonium chloride solution is 1:1.2, the mineralization temperature is controlled at 50°C, and the obtained ore dissolution solution enters the ore dissolution and slag removal zone 2 through the first mixed liquid outlet 8;

[0068] S2. In the ore removal residue removal zone 2, the molten ore is settled by the settling wedge assembly and then enters the first filter 13 through the second mixed liquid outlet 9. The resulting filtrate returns to the ore removal residue removal zone 2, and the resulting residue is transported to the cement plant. The supernatant from the ore removal residue removal zone 2 overflows through multiple first overflow pipes 5 to the iron and aluminum removal zone 3.

[0069] S3. In the iron removal and aluminum removal zone 3, the precipitant sprayer 7 sprays sodium hydroxide with a molar concentration of 0.01-0.02 mol / L onto the surface of the overflow liquid. The volume ratio of sodium hydroxide to overflow liquid is 1:(10-15). After the mixed liquid is settled by the settling wedge assembly, it enters the second filter 14 through the third mixed liquid outlet 10. The resulting filtrate returns to the iron removal and aluminum removal zone 3 again, and the resulting filter residue is transported to the steel plant. The supernatant of the iron removal and aluminum removal zone 3 overflows into the leachate storage area 4 through multiple second overflow pipes 6 and is discharged from the leachate outlet 24.

[0070] The results showed that the calcium ion concentration in the leaching solution was 0.7 mol / L, the iron ion concentration was 0.001 mol / L, the aluminum ion concentration was 0.001 mol / L, and the extraction rate of calcium ions in the magnesium slag was 92%.

[0071] Control the flow rate of the leaching liquid to 1.5-2m 3 / h, and after the leaching liquid is discharged to the carbon dioxide absorption and mineralization device, online carbon dioxide detectors are installed at the gas inlet and outlet to detect the carbon dioxide concentration. The calculated carbon dioxide absorption rate is 92%, the whiteness of the obtained calcium carbonate is 98.5, and the purity is 99%.

[0072] Comparative Example 1

[0073] The device in Example 1 is used, but the supernatant in the slag slag zone 2 overflows to the leachate storage tank through multiple first overflow pipes 5 without passing through the iron and aluminum removal zone. The magnesium slag in Example 1 is treated in the following specific treatment method:

[0074] S1, magnesium slag enters the ore dissolution zone 1 through the feeding mechanism 20, the feeding speed is 550kg / h, the ammonium chloride solution is replenished from the ammonium chloride tank through the PLC-controlled metering pump, the concentration of the ammonium chloride solution is 10%, the mass ratio of magnesium slag to ammonium chloride solution is 1:1.2, the mineralization temperature is controlled at 50°C, and the obtained ore dissolution solution enters the ore dissolution and slag removal zone 2 through the first mixed liquid outlet 8;

[0075] S2. In the ore removal residue removal zone 2, the molten ore is settled by the settling wedge assembly and then enters the first filter 13 through the second mixed liquid outlet 9. The resulting filtrate returns to the ore removal residue removal zone 2, and the resulting residue is transported to the cement plant. The supernatant in the ore removal residue removal zone 2 overflows into the leachate storage tank through multiple first overflow pipes 5.

[0076] The results showed that the calcium ion concentration in the leaching solution was 0.6 mol / L, the iron ion concentration was 0.1 mol / L, the aluminum ion concentration was 0.05 mol / L, and the extraction rate of calcium ions in the magnesium slag was 85%.

[0077] Control the flow rate of the leaching liquid to 1.5-2m 3 / h, and after the leaching liquid is discharged to the carbon dioxide absorption and mineralization device, online carbon dioxide detectors are installed at the gas inlet and outlet to detect the carbon dioxide concentration. The calculated carbon dioxide absorption rate is 90%, and the whiteness of the obtained calcium carbonate is 88.4 and the purity is 92%.

[0078] Comparative Example 2

[0079] The magnesium slag in Example 1 was treated using a conventional stirred reactor type ore dissolving device. The specific treatment method is as follows:

[0080] S1. Add 500 kg of the above-mentioned magnesium slag powder and 6 t of 10% ammonium chloride solution by mass into a reactor equipped with a stirring device, control the mineralization temperature to 40°C, and react for 2 hours;

[0081] S2. After the reaction is completed, the leaching liquid is discharged through the discharge port and then filtered;

[0082] The results showed that the calcium ion concentration in the leaching solution was 0.5 mol / L, the iron ion concentration was 0.2 mol / L, the aluminum ion concentration was 0.08 mol / L, and the extraction rate of calcium ions in the magnesium slag was 80%.

[0083] Control the flow rate of the leaching liquid to 1.5-2m 3 / h, and discharge the leaching liquid into the carbon dioxide absorption and mineralization device. Install online carbon dioxide detectors at the gas inlet and outlet to detect the carbon dioxide concentration. The carbon dioxide absorption rate is calculated to be 85%. The whiteness of the obtained calcium carbonate is 83.5 and the purity is 87.

[0084] The treatment effects of Example 2 and Comparative Example 1 on magnesium slag are shown in Table 2.

[0085] Table 2 Treatment effects of Example 2 and Control Example 1

[0086]

[0087] In summary, the ore dissolving device of the present invention is used to leach magnesium slag, and the leaching liquid is used to purify the flue gas of the power plant. It can not only fully leach the calcium in the magnesium slag with a calcium extraction rate of more than 90%, but also effectively eliminate impurities such as iron and aluminum in the ore dissolving liquid, thereby improving the whiteness and purity of calcium carbonate.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A ore dissolving device, characterized in that: The invention comprises a tank body and a ore dissolution area (1), an ore dissolution slag removal area (2), an iron and aluminum removal area (3) and a leaching liquid storage area (4) arranged inside the tank body. The ore dissolution zone (1) is connected to the ore dissolution and slag removal zone (2). A plurality of first overflow pipes (5) are evenly arranged in the desolventizing slag zone (2), and one end of each of the first overflow pipes (5) is connected to the desolventizing slag zone (2), and the other end is connected to the iron and aluminum removal zone (3); A plurality of second overflow pipes (6) are arranged in the iron removal and aluminum removal area (3), and one end of each of the second overflow pipes (6) is connected to the iron removal and aluminum removal area (3), and the other end is connected to the leaching liquid storage area (4); One or more precipitant sprayers (7) are also arranged above the iron and aluminum removal zone (3); A plurality of settling wedge assemblies are arranged inside the slag removal zone (2) and the iron and aluminum removal zone (3), wherein the settling wedge assemblies include a plurality of first settling wedges (15) inclined inwardly and a plurality of second settling wedges (16) inclined outwardly, wherein the second settling wedges (16) are arranged above the first settling wedges (15); The method for dissolving ore in the ore dissolving device comprises the following steps: S1, magnesium slag enters the ore dissolution zone (1) through the feeding mechanism (20), the magnesium slag is leached by ammonium chloride, and the resulting ore dissolution solution enters the ore dissolution and slag removal zone (2) through the first mixed solution outlet (8); S2, in the ore removal and slag removal zone (2), the ore removal solution is settled through the settling wedge assembly and then enters the first filter (13) through the second mixed solution outlet (9), and the obtained filtrate is returned to the ore removal and slag removal zone (2) again; the supernatant of the ore removal and slag removal zone (2) overflows to the iron and aluminum removal zone (3) through a plurality of first overflow pipes (5); S3, in the iron removal and aluminum removal zone (3), the precipitant sprayer (7) sprays the precipitant on the surface of the overflow liquid, and the mixed liquid is settled through the settling wedge assembly and enters the second filter (14) through the third mixed liquid outlet (10), and the obtained filtrate returns to the iron removal and aluminum removal zone (3) again; the supernatant of the iron removal and aluminum removal zone (3) overflows to the leaching liquid storage zone (4) through a plurality of second overflow pipes (6) and is discharged from the leaching liquid outlet (24); When the leaching solution is used for mineralization and absorption of carbon dioxide, the whiteness and purity of calcium carbonate can be significantly improved, and the added value of the product can be increased. The absorption rate of carbon dioxide can reach more than 95%, and during the operation, the ammonia generated by magnesium slag and ammonium chloride can form a buffer solution with the ammonium chloride. Therefore, during the mineralization process, there is no need to add acid or alkali to adjust the pH, and there is no need to add a crystal form control agent.

2. The ore dissolving device according to claim 1, characterized in that: The bottoms of the ore dissolution zone (1), the ore dissolution slag removal zone (2) and the iron and aluminum removal zone (3) are either or all of a conical structure, and the bottoms of the ore dissolution zone (1), the ore dissolution slag removal zone (2) and the iron and aluminum removal zone (3) are respectively provided with a first mixed liquid outlet (8), a second mixed liquid outlet (9) and a third mixed liquid outlet (10); The second mixed liquor outlet (9) is connected to the upper part of the desolventizing and slag removal zone (2) through a first pipeline (11), and the third mixed liquor outlet (10) is connected to the upper part of the iron and aluminum removal zone (3) through a second pipeline (12).

3. The ore dissolving device according to claim 2, characterized in that: The first pipe (11) and the second pipe (12) are respectively provided with a first filter (13) and a second filter (14).

4. The ore dissolving device according to claim 1, characterized in that: The top of the ore dissolving area (1) is provided with a feed port (17), a liquid replenishing port (18) and an exhaust gas discharge port (19); a feed discharge mechanism (20) is provided on the feed port (17); and an iron removal component (21) is provided at one end of the feed discharge mechanism (20) close to the feed port (17).

5. The ore dissolving device according to claim 1, characterized in that: A stirring mechanism (22) is arranged inside the ore dissolving area (1), and a circulating water heating layer (23) is arranged outside the ore dissolving area (1).

6. The ore dissolving device according to claim 1, characterized in that: An online liquid level meter is provided inside the ore dissolution zone (1), and an online viscosity detector is installed at the first mixed liquid outlet (8); The bottom of the leachate storage area (4) is provided with an leachate outlet (24), and an online calcium ion monitor and a flow meter are installed at the leachate outlet (24); The valves at the first mixed liquid outlet (8) and the leaching liquid outlet (24) are both pneumatic regulating valves.

7. The ore dissolving device according to claim 1, characterized in that: In step S1, the feeding rate of magnesium slag is 550-700 kg / h, the mass ratio of magnesium slag to ammonium chloride is 1:(1.0-1.2), wherein the mass concentration of ammonium chloride is 6-12%.

8. The ore dissolving device according to claim 1, characterized in that: In step S3, the precipitant includes any one or more of ammonia water, sodium hydroxide, sodium carbonate and ammonium bicarbonate, and the volume of the precipitant to the overflow liquid is 1:(10-15), wherein the molar concentration of the precipitant is 0.01-0.02 mol / L.

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